/Engine/Source/Runtime/Engine/Classes/Materials/MaterialLayersFunctions.h
int32 AddLayerCopy ( const [FMaterialLayersFunctionsRuntimeData](API\Runtime\Engine\Materials\FMaterialLayersFunctionsRuntimeD-) & Source, const [FMaterialLayersFunctionsEditorOnlyData](API\Runtime\Engine\Materials\FMaterialLayersFunctionsEditorOn-) & SourceEditorOnly, int32 SourceLayerIndex, bool bVisible, EMaterialLayerLinkState LinkState )